153 lines
5.0 KiB
Markdown
153 lines
5.0 KiB
Markdown
---
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name: source-aware-sast
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description: Practical source-aware SAST and AST playbook for semgrep, ast-grep, gitleaks, and trivy fs
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---
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# Source-Aware SAST Playbook
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Use this skill for source-heavy analysis where static and structural signals should guide dynamic testing.
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## Fast Start
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Run tools from repo root and store outputs in a dedicated artifact directory:
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```bash
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mkdir -p /workspace/.strix-source-aware
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```
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## Baseline Coverage Bundle (Recommended)
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Run this baseline once per repository before deep narrowing:
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```bash
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ART=/workspace/.strix-source-aware
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mkdir -p "$ART"
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semgrep scan --config p/default --config p/golang --config p/secrets \
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--metrics=off --json --output "$ART/semgrep.json" .
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# Build deterministic AST targets from semgrep scope (no hardcoded path guessing)
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python3 - <<'PY'
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import json
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from pathlib import Path
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art = Path("/workspace/.strix-source-aware")
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semgrep_json = art / "semgrep.json"
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targets_file = art / "sg-targets.txt"
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try:
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data = json.loads(semgrep_json.read_text(encoding="utf-8"))
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except Exception:
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targets_file.write_text("", encoding="utf-8")
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raise
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scanned = data.get("paths", {}).get("scanned") or []
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if not scanned:
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scanned = sorted(
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{
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r.get("path")
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for r in data.get("results", [])
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if isinstance(r, dict) and isinstance(r.get("path"), str) and r.get("path")
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}
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)
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bounded = scanned[:4000]
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targets_file.write_text("".join(f"{p}\n" for p in bounded), encoding="utf-8")
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print(f"sg-targets: {len(bounded)}")
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PY
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xargs -r -n 200 sg run --pattern '$F($$$ARGS)' --json=stream < "$ART/sg-targets.txt" \
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> "$ART/ast-grep.json" 2> "$ART/ast-grep.log" || true
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gitleaks detect --source . --report-format json --report-path "$ART/gitleaks.json" || true
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trufflehog filesystem --no-update --json --no-verification . > "$ART/trufflehog.json" || true
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# Keep trivy focused on vuln/misconfig (secrets already covered above) and increase timeout for large repos
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trivy fs --scanners vuln,misconfig --timeout 30m --offline-scan \
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--format json --output "$ART/trivy-fs.json" . || true
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```
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## Semgrep First Pass
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Use Semgrep as the default static triage pass:
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```bash
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# Preferred deterministic profile set (works with --metrics=off)
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semgrep scan --config p/default --config p/golang --config p/secrets \
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--metrics=off --json --output /workspace/.strix-source-aware/semgrep.json .
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# If you choose auto config, do not combine it with --metrics=off
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semgrep scan --config auto --json --output /workspace/.strix-source-aware/semgrep-auto.json .
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```
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If diff scope is active, restrict to changed files first, then expand only when needed.
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## AST-Grep Structural Mapping
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Use `sg` for structure-aware code hunting:
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```bash
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# Ruleless structural pass over deterministic target list (no sgconfig.yml required)
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xargs -r -n 200 sg run --pattern '$F($$$ARGS)' --json=stream \
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< /workspace/.strix-source-aware/sg-targets.txt \
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> /workspace/.strix-source-aware/ast-grep.json 2> /workspace/.strix-source-aware/ast-grep.log || true
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```
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Target high-value patterns such as:
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- missing auth checks near route handlers
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- dynamic command/query construction
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- unsafe deserialization or template execution paths
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- file and path operations influenced by user input
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## Tree-Sitter Assisted Repo Mapping
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Use tree-sitter CLI for syntax-aware parsing when grep-level mapping is noisy:
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```bash
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tree-sitter parse -q <file>
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```
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Use outputs to improve route/symbol/sink maps for subsequent targeted scans.
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## Secret and Supply Chain Coverage
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Detect hardcoded credentials:
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```bash
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gitleaks detect --source . --report-format json --report-path /workspace/.strix-source-aware/gitleaks.json
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trufflehog filesystem --json . > /workspace/.strix-source-aware/trufflehog.json
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```
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Run repository-wide dependency and config checks:
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```bash
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trivy fs --scanners vuln,misconfig --timeout 30m --offline-scan \
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--format json --output /workspace/.strix-source-aware/trivy-fs.json . || true
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```
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## JavaScript-Side Coverage
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For frontends and Node services, layer these on top of the language-agnostic
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passes above:
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```bash
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retire --path . --outputformat json --outputpath /workspace/.strix-source-aware/retire.json || true
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eslint --no-config-lookup --rule '{"no-eval":2,"no-implied-eval":2}' \
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-f json -o /workspace/.strix-source-aware/eslint.json . || true
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```
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When you hit a minified bundle, run `js-beautify <file>` for a readable
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view before greppping — and use `jshint --reporter=unix <file>` as a
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lighter syntax/anti-pattern check when ESLint is over-eager. The
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`JS-Snooper` / `jsniper.sh` tools (in `katana.md`) are the right next
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step to mine those bundles for endpoint candidates.
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## Converting Static Signals Into Exploits
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1. Rank candidates by impact and exploitability.
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2. Trace source-to-sink flow for top candidates.
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3. Build dynamic PoCs that reproduce the suspected issue.
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4. Report only after dynamic validation succeeds.
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## Anti-Patterns
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- Do not treat scanner output as final truth.
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- Do not spend full cycles on low-signal pattern matches.
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- Do not report source-only findings without validation evidence.
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